ES51926 3000 Counts Smart DMM Features General description z 3000 counts LCD display z 3V DC power supply ES51926 is an integrated ADC with 3000 counts z Conversion rate: 4 times/s (voltage mode) LCD display driver. It could support fully z Full automatic measurement: automatic DMM function measurement. In *Voltage/Current: AC/DC auto scanning voltage or current mode, the AC or DC signals & auto range: 3.000V~1000V z auto scanning. In R/D/C (passive component) *Resistance/Diode/Capacitance(RDC scan) mode, (Taiwan patent no.: 326361) capacitance or diode measurements are allowed Auto scanning & auto range: by fully automatic detection. A single key and Resistance: 300.0Ω~3.000MΩ simple switch could select all measurements. Capacitance: 3.000nF~300.0uF Expensive and bulky mechanical range switches resistance (including continuity), (Taiwan patent no.: 323347,453443) are not required. A non-contact electric field Push functions detector (EF mode) is built-in for ac voltage Function selection by single key measurement also. Other features including Range change function range control, data hold, max/min hold, VAHz Hold function and back light function are available. For power MAX/MIN function saving, an auto power off & re-power on scheme VAHZ function are built-in. A sleep output is the indication of Back light function entering auto power off mode. z Support non-contact voltage detection z High voltage (> 30V) indication of LCD display for voltage measurement (Taiwan patent no.: 234661) z Built-in HCF(high crest factor detection) function in AC mode z OL level selection (600V/1000V/1500V) z Band-gap reference voltage output z Auto power off (3min. or 10min.) & re-power on z Sleep output indication z On-chip buzzer driver z Low battery detection Application z Smart digital multi-meter z Smart clamp meter Ver 2.9 1 10/06/25 ES51926 3000 Counts Smart DMM 55 60 65 75 80 50 45 Cyrustek. com.tw 85 ES51926 90 95 40 35 25 20 15 5 100 10 30 NC NC NC NC NC ACEN BUZOUT APOSEL BUZIN SLEEP R1K R9KCA+ CANC VR1 VAVA+ ADP SGND VR VRH NC OHMC1 OHMC2 AGND LBAT CREF+ CREFCINT CAZ BUFF RAZ IVSH IVSL OVX OVH OVSG OR1 VR5 VR4 VR3 VR2 TEST5 ACVL ACVH ADI ADO OHMC4 OHMC3 SEG11 SEG10 NC NC SEG09 SEG08 SEG07 SEG06 SEG05 SEG04 SEG03 SEG02 SEG01 OSC2 OSC1 BKSEL CESEL C+ CVVV+ V+ DGND AGND 70 SEG12 SEG13 SEG14 SEG15 CLAMP VON AON FA FUA FC3 FC2 FC1 HOLD SEL VAHZ RANGE MAX/MIN BKLIT EFEN BP1 BP2 BP3 BP4 ANNUNC BKOUT Pin Assignment Pin Description Pin No Symbol Type 1 2 AGND LBAT P I 3 4 5 6 7 8 CREF+ CREFCINT CAZ BUFF RAZ I/O I/O O I O O 9 10 IVSH IVSL I I Ver 2.9 Description Analog ground. Low battery configuration. If 3V battery is used, connect it to DGND. The default low-battery threshold voltage is –2.3V. If 9V battery is used, the low battery enunciator is displayed when the voltage of this pin is less than VRH (-1.2V) Positive connection for reference capacitor. Negative connection for reference capacitor. Integrator output. Connect to integral capacitor Auto-zero capacitor connection. Buffer output pin. Connect to integral resistor Buffer output pin in high-speed mode. Connect to high-speed integral resistor. High current measurement input. Low current measurement input 2 10/06/25 ES51926 3000 Counts Smart DMM 11 12 13 14 15 16 17 18 19 20 OVX OVH OVSG OR1 VR5 VR4 VR3 VR2 TEST5 ACVL I I I O O O O O I/O I 21 ACVH I 22 23 24 25 26 27 28 29 30 31 32 33 ADI ADO OHMC4 OHMC3 OHMC2 OHMC1 NC VRH VR SGND ADP VA+ I O O O O O O I I I I 34 VA- I 35 36 37 38 39 40 41 42 43 44 45 46 – 50 51 VR1 NC CACA+ R9K R1K SLEEP BUZIN APOSEL BUZOUT ACEN NC BKOUT I I/O I/O O O O I I O O O 52 ANNUNC O 53 54 55 56 57 58 59 60 61 BP4 BP3 BP2 BP1 EFEN BKLIT MAX/MIN RANGE VAHz O O O O I I I I I Ver 2.9 Input high voltage for resistance/capacitor measurement Output connection for resistance/capacitor measurement Sense low voltage for resistance measurement Reference resistor connection for 300.0Ω range Voltage measurement ÷10000 attenuated (1000V) Voltage measurement ÷1000 attenuated (300.0V) Voltage measurement ÷100 attenuated (30.00V) Voltage measurement ÷10 attenuated (3.000V) Test pin DC signal low input in ACV/ACA mode. Connect to negative output of external AC to DC converter. DC signal high input in ACV/ACA mode. Connect to positive output of external AC to DC converter. Negative input of internal AC to DC OP Amp. Output of internal AC to DC OP Amp. Filter capacitor connection for resistance mode Filter capacitor connection for resistance mode Filter capacitor connection for resistance mode Filter capacitor connection for resistance mode Output of band-gap voltage reference. Typically –1.2V Reference input voltage connection. Typically –400mV Signal Ground. Measurement input in ADP mode For ADP mode. De-integrating voltage positive input. The input should be higher than VA-. For ADP mode. De-integrating voltage negative input. The input should be lower than VA+. Measurement input. Negative auto-zero capacitor connection for capacitor measurement Positive auto-zero capacitor connection for capacitor measurement Connect to a precise 9KΩ resister for capacitor measurement. Connect to a precise 1KΩ resister for capacitor measurement. Sleep mode indicator, asserts low in SLEEP mode. Normal V+ output. Pull to V- to enable the BUZOUT. Auto power off idle time selection. Outputs a 2KHz audio frequency signal for driving piezoelectric buzzer Output to V- when AC mode inactive and output to V+ in AC mode. If BKLIT function is enabled, this pin will change from –3V to +3V for 60 sec, once press BKLIT pin again within 60 sec, this pin will change back to –3V. Square wave output at the backplane frequency, synchronized to BP1. ANNUNC can be used to control display annunciator. Connect a LCD segment to ANNUNC to turn it on; connect an LCD segment to its back plane to turn it off. LCD backplane 4 LCD backplane 3 LCD backplane 2 LCD backplane 1 Pull-low to enable non-contact AC voltage detection Back light function. Pulse low to set BKOUT pin output. Pulse to V- to enable MAX/MIN function. Pulse to V- to enable manual mode and manual range selection. Pulse to V- to enable VAHz mode. 3 10/06/25 ES51926 3000 Counts Smart DMM 62 63 64 65 66 67 68 69 70 71 72 – 77 78 – 79 80 – 88 89 90 SEL HOLD FC1 FC2 FC3 FUA FA AON VON CLAMP SEG15 – 10 NC SEG09 - 01 OSC2 OSC1 91 BKSEL 92 93 94 95 96 97 98 99 100 CESEL C+ CVVV+ V+ DGND AGND I I I I I I I I I I O O I O Pulse to V- to select target measurement Pulse to V- to enable HOLD function. Switch 1 for function selection. Switch 2 for function selection. Switch 3 for function selection. Switch 1 for current measurement selection. Switch 2 for current measurement selection. Pull to high to sense current measurement priority in auto scan mode Pull to high to sense voltage measurement priority in auto scan mode Switch for clamp meter application function LCD segment line 10 – 15 LCD segment line 01 – 09 Crystal oscillator input connection Crystal oscillator output connection When pulled to V-, an auto back light configuration is allowed. Configure a low level applied to BKLIT larger than 1 second, the I BKOUT will be active. If BKLIT is back to high level, the BKOUT would be inactive. I OL selection feature control pin. O Positive capacitor connection for on-chip DC-DC converter. O Negative capacitor connection for on-chip DC-DC converter. P Negative supply voltage. Connecting to battery negative terminal. P Negative supply voltage. Connecting to battery negative terminal. P/O Output of on-chip DC-DC converter. P/O Output of on-chip DC-DC converter. G Digital ground. G Analog ground. Absolute Maximum Ratings Characteristic Supply Voltage (V- to AGND) Analog Input Voltage V+ AGND/DGND Digital Input Power Dissipation. Flat Package Operating Temperature Storage Temperature Ver 2.9 Rating -4V V- -0.6 to V+ +0.6 V+ ≥ (AGND/DGND+0.5V) AGND/DGND ≥ (V- -0.5V) V- -0.6 to DGND +0.6 500mW 0℃ to 70℃ -25℃ to 125℃ 4 10/06/25 ES51926 3000 Counts Smart DMM Electrical Characteristics TA=25℃, V- = -3V Parameter Power supply Operating supply current In Scan AC/DC mode Voltage roll-over error Voltage nonlinearity Input Leakage Low battery flag voltage Zero input reading Peak to peak backplane drive voltage Counter time base period Reference voltage and open circuit voltage for 300Ω measurement Open circuit voltage for Ω measurement (except 300Ω) Internal pull-high to 0V current AC frequency response at 6.000V Range AC input response for scan mode AC/DC voltage scan mode sensitivity@1kHz AC/DC current scan mode sensitivity@1kHz RDC scan mode RES sensitivity Symbol Test Condition VIDD Normal operation ISS In sleep mode REV 10MΩ input resistor Min. -3.5 — — — Typ. -3.0 2.5 0.6 — Max -2.5 — 2.5 ±0.1 Units V mA µA %F.S1 Best case straight NLV line — — ±0.1 %F.S -10 -2.4 -000 1 -2.3 000 10 -2.2 +000 PA V counts 3.0 3.15 3.3 V — 1 — sec -1.33 -1.23 -1.13 V -0.86 -0.78 -0.70 V — 1.2 — µA V- to AGND 10MΩ input resistor -3.5V≤ V ≤-2.2V VREF fOSC = 4MHZ 100KΩ resistor between VRH and AGND Ω and Continuity Mode Between V- pin and HOLD, RANGE, SEL,FC1-3,FUA, FA, VON, AON, CLAMP, BKLIT, MAXMIN ±1% ±5% VR1(10MΩ input impedance) ADP, IVSL and IVSH Parasitic capacitance allowed in 3.000MΩ range Forward voltage RDC scan mode DIODE sensitivity RDC scan mode CAP sensitivity Reference voltage temperature 100KΩ resister coefficient TCRF Between VRH 0℃<TA<70℃ 3nF – 3.0µF Capacitance measurement accuracy 30µF ~ 30mF — — 10 40-400 — 400-2000 — — 50000 HZ Hz 300 450 600 mV 8 10 12 mV — — 200 pF — 400 0.8 — — — V pF — 50 — ppm/℃ -1.5 -5 -2.0 — — — 1.5 5 2.0 %F.S counts %F.S -5 — 5 counts Note: 1.Full Scale Ver 2.9 5 10/06/25 ES51926 3000 Counts Smart DMM Functional Description 1. Operation Modes 1.1 Voltage Measurement A re-configurable voltage divider automatically provides a suitable range in voltage measurement mode. The following table summarizes the full-scale ranges in each configuration. Configuration VR1 VR2 VR3 VR4 VR5 Full Scale Range 300.0mV* 3.000V** 30.00V 300.0V 1000V*** Divider Ratio 1 1/10 1/100 1/1000 1/10000 Resister Connection VR1 (10MΩ) VR2 (1.111MΩ) VR3 (101KΩ) VR4 (10KΩ) VR5 (1KΩ) Note: * Exists in manual mode only by RANGE key control **This range is the default range for auto range & auto scan mode *** Depends on CESEL selection 1.1.1 OL selection ES51926 has a OL display selection feature archived by configuring a CESEL pin. If pin CESEL is connected to V-, ES51926 will have a 600.0V overflow level in DCV and ACV mode. If pin CESEL is connected to DGND, the ES51926 will have a 1010V overflow level in DCV mode and have a 1010V overflow level in ACV mode also. When CE is floating, a 1500V overflow level in DCV mode but ACV is still 1010V overflow level. The meter will Show OL when the measuring signal reaches the overflow level with beeper warning. The configuration of CESEL is listed below. CESEL VDGND Floating Ver 2.9 DCV 600.0V 1010V 1500V 6 ACV 600.0V 1010V 1010V 10/06/25 ES51926 3000 Counts Smart DMM 1.1.2 HCF detection ES51926 provides detection of high-crest-factor (HCF) signal in ACV auto range mode. ES51926 senses the signal and determines it as HCF if the Vpp is large enough. Once the signal is determined as HCF, ES51926 will jump up one measuring range regardless of current measurement value. It takes 60ms to jump one range up. The jumping up process will continue until the maximum range is reached. With HCF detection, a more accurate result could be obtained. For example, when a input signal with Vpp=200V, Vrms=40V(CF=5) was applied, traditional DMM might stay at 30V range but shows counts with the amount of error up to 10% or even bigger. The error rises from limited input/output swing at internal ADC. With HCF detection, DMM will stay at 300V range and exhibits more accurate results. 1.1.3 EF mode ES51926 supports a non-contact ac voltage measurement, which is called electric field measurement also. The EF mode is selected by SEL key when EF_EN is active. The ADC input is configured from ADP pin vs. SGND. When no or less electric field is detected, the LCD shows “EF”. If the detector senses electric field, the strength will be showed on LCD by “-“ not digits type. Level 1(weak) is “-“ and the level 4(strong) is “----“. Additional beeper will be output from BUZOUT pin. The buzzer frequency depends on the strength of electric field also. The Faster beeper means the stronger electric field (ac voltage) is sensed. Ver 2.9 7 10/06/25 ES51926 3000 Counts Smart DMM 1.2 Current Measurement 1.2.1 For multi-meter application ES51926 has 2 automatic and 1 manual current measurement modes for multi-meter. The following table summarizes the full-scale range of each mode. When ES51926 operates in the current measurement modes for multi-meter, it takes high input from pin IVSH or IVSL, low input from pin SGND and reference voltage from pin VR. Mode Automatic1 Automatic2 Manual Full Scale 300.0µA / 3000µA 30.00mA / 300.0mA 30.00A Input Terminal IVSL/IVSH V.S. SGND IVSL/IVSH V.S. SGND IVSH V.S. SGND Full scale 150.0mV 150.0mV 150.0mV 1.2.2 For clamp meter application ES51926 has 2 automatic and 4 manual current measurement modes for Clamp meter. The following table summarizes the full-scale range of each mode. When ES51926 operate in the automatic mode1&2, it takes high input from IVSH/IVSL (higher range/lower range), low input from SGND and reference voltage from VR. When ES51926 operate in the manual mode1~4, it takes high input from ADP, low input from SGND and reference voltage from VA+ & VA-. Mode Automatic1 Automatic2 Manual1 Manual2 Manual3 Manual4 Ver 2.9 Full Scale 300.0A / 3000A 30.00A / 300.0A 3.000A 30.00A 300.0A 3000A Input Terminal IVSL/IVSH V.S. SGND IVSL/IVSH V.S. SGND ADP V.S. SGND ADP V.S. SGND ADP V.S. SGND ADP V.S. SGND 8 Full scale 300.0mV 300.0mV 300.0mV 300.0mV 300.0mV 300.0mV 10/06/25 ES51926 3000 Counts Smart DMM 1.3 Resistance Measurement A re-configurable divider automatically provides a suitable full-scale range in resistance measurement mode. The following table summarizes the full-scale ranges and the reference resistors in each configuration. Configuration OR1 OR2 OR3 OR4 OR5 OR6 Full Scale Range 300.0Ω* 3.000KΩ 30.00KΩ 300.0KΩ 3.000MΩ 30.00MΩ** Relative Resistor OR1 VR5 VR4 VR3∥VR1 VR2∥VR1 VR1 Equivalent value 100Ω 1KΩ 10KΩ 100KΩ 1MΩ 10MΩ Note: * When auto scan mode is set, continuity check is implemented in this range ** When auto scan mode is set, the 30.00MΩ range is omitted 1.3.1 Continuity check Continuity check shares the same configuration with 300.0Ω manual resistance measurement mode and has buzzer output to indicate continuity. The buzzer generates 2KHz beep whenever the reading is less than 30Ω. 1.4 Diode Measurement Diode measurement mode shares the same configuration with 3.000V manual voltage measurement mode and has buzzer output to indicate continuity. The buzzer generates a 2KHz sound whenever the reading is less than 30mV. If the test circuit is open or the voltage drop between the two ports of the device (diode) under test is larger than 2V, the LCD panel will show “OL”. Ver 2.9 9 10/06/25 ES51926 3000 Counts Smart DMM 1.5 Capacitance Measurement The following table summarizes the eight ranges of capacitance measurement mode: Configuration C1 C2 C3 C4 C5 C6 C7 C8 Full Scale Range 3.000nF 30.00nF 300.0nF 3.000uF 30.00uF 300.0uF 3.000mF* 30.00mF** Relative Resistor 20kΩVR+100kΩ 20kΩVR+100kΩ 101kΩ 10kΩ R9K / R1K R9K / R1K R9K / R1K R9K / R1K Note: * & ** The C7-C8 both range is not available for auto scan mode In order to obtain an accurate reading, a capacitor must be discharged before measurement begins. The chip has a built-in discharge mode to automatically discharge the capacitor. In discharge mode, the LCD displays “dIS.C” Discharging through the chip is quite slow. We recommend users to discharge the capacitor with some other apparatus. 1.6 Auto power off mode (APO) 1.6.1 Idle Time selection ES51926 has a default auto power off function. If the meter is idle for more than the given Idle Time, the chip automatically turns the power off. The idle time to trigger the auto power off function is determined by pin ‘APOSEL’. If pin APOSEL is connected to V-, the Idle Time will be set to 3 minutes. If pin APOSEL is connected to DGND or floating, the Idle Time will be set to 10 minutes. When APO happens, the state of the meter is saved. If the APO is necessary to be cancelled, power on the ES51926 when any of the push key, except for HOLD, is pressed down simultaneously. Ver 2.9 10 10/06/25 ES51926 3000 Counts Smart DMM 1.6.2 Sleep output The meter enters sleep mode after auto power-off or push SEL key to last for 2s. The SLEEP pin asserts low (-3V) in the sleep mode, and asserts high (+3V, not 0V) after re-power on. 1.6.3 Re-power on After auto power-off is active, pushing any of the push function or changing the measurement function can turn on the meter again. If the meter is re-powered on by changing measurement function, the saved state is cleared. If the meter is re-powered on by push functions, the chip restores the saved state and enters HOLD mode. The LCD displays the saved value except for the auto scan mode. Ver 2.9 11 10/06/25 ES51926 3000 Counts Smart DMM 2. Functional Modes Table Measurement mode depends on the logic level of FC1, FC2, FC3, FUA, FA, VON, AON and CLAMP. FC1 1 1 1 1 1 1 1 0 0 0 1 1 FC2 FC3 FUA FA VON AON CLAMP X 0 X X X 0 0 X 0 1 0 X 1 0 X 0 0 0 X 1 0 X 0 0 1 X 1 0 X 0 X X 1 X 1 X 0 1 0 0 X 1 X 0 0 0 0 X 1 1 0 X X X X X 0 1 X X 0 X 1 1 1 X X 0 X 1 0 1 X X 0 X 1 1 1 X X 0 X 1 Functional Mode(pushing SEL key) VAUTOÆVACÆVDCÆEF*ÆVAUTOÆ… IAUTOÆIACÆIDCÆIAUTOÆ…(uA) IAUTOÆIACÆIDCÆIAUTOÆ…(mA) IAUTOÆIACÆIDCÆIAUTOÆ…(A) VAUTOÆVACÆVDCÆVAUTOÆ… IAC(300.0A/3000A) IAC(30.00A/300.0A) RDCAUTOÆRÆDÆCÆRDCAUTOÆ… IAUTOÆIACÆIDCÆIAUTOÆ…(3.000A) IAUTOÆIACÆIDCÆIAUTOÆ…(30.00A) IAUTOÆIACÆIDCÆIAUTOÆ…(300.0A) IAUTOÆIACÆIDCÆIAUTOÆ…(3000A) Input VR1,ADP IVSH/IVSL IVSH/IVSL IVSH VR1 IVSH/IVSL IVSH/IVSL VR1 ADP ADP ADP ADP Note: * EF mode could be selected when EF_EN is active. 3. Push Function All the enabled push functions will be reset when the measurement mode is changed by external switch. Change measurement mode by SEL function will reset enabled RANGE, HOLD, MAX/MIN, and VAHz functions. The following table lists the available function versus every measurement mode. SEL RANGE HOLD MAX/MIN VSCAN O X X X VAC O O O O VDC O O O O EF O X X X ISCAN O X X X IAC O O* O O IDC O O* O O RDCSCAN O X X X Resistance O O O O Continuity O X O O Diode O X O O Capacitance O O O O Note: For ADP input, RANGE is not available Ver 2.9 12 VAHz O O O X O O O X X X X X BKLIT O O O O O O O O O O O O 10/06/25 ES51926 3000 Counts Smart DMM 3.1 Select function When power on or SEL key is pressed longer than one second, ES51926 will be power-on reset to auto scan mode, which scanning mode is determined by [FC1-FC3] function set. In auto scan mode, the ES51926 automatically selects the appropriate measurement mode and range. Pushing the SEL key less than one second could select the target measurement function. Pushing the key larger than two seconds, the ES51926 will enter power down mode. If power down mode is entered, only press SEL key to last for one second or apply the power to Vterminal could re-power on the ES51926. The following figure shows the state transition. Push SEL key < 1s V/A ac/dc auto scan Push SEL key > 1s Power on reset AC mode measurement DC mode measurement EF* mode measurement Push SEL key > 2s Æ enter power down mode R/D/C auto scan Continuity measurement Resistance measurement Diode measurement Capacitance measurement Push SEL key < 1s Note: * Available when EF_EN is active only Ver 2.9 13 10/06/25 ES51926 3000 Counts Smart DMM 3.2 Range function RANGE pin switches to and from automatic and manual mode, and while in manual mode, changes the full-scale range. The following figure shows the state transition. 1 push < 1 sec Automatic Mode Manual Mode 1 push > 1 sec Range up 1 push < 1 sec 3.3 Hold and delay-hold function The data hold mode makes the meter stop updating the LCD panel. This mode can be nested in most of the special modes. In auto scanning mode, the HOLD key is not available. Enabling hold function in automatic mode makes the meter switch to manual mode. Hold function can be cancelled by changing the measurement mode, pressing RANGE, or push HOLD again. The delay-hold function is enabled when HOLD key is pressed larger than 2 seconds. When delay-hold function is entered successfully, the meter will stop to update the LCD data after six seconds delayed. During the six seconds waiting, the HOLD symbol on LCD panel will be blinking. Normal mode Push < 2s HOLD mode (Auto/Manual) Push < 2s (Manual) Push > 2s Push < 2s Ver 2.9 Push > 2s 6sec past Delay State (Auto/Manual) 14 10/06/25 ES51926 3000 Counts Smart DMM 3.4 Max/Min + Hold function The meter displays the maximum or minimum value of the input in Max/Min mode. When MAX/MIN is pressed for the first time, the meter displays the maximum value. The meter displays the minimum value, when it is pressed again. When MAX/MIN is pressed for the third time, the meter displays current value. The meter returns to normal operation if MAX/MIN is pressed and held for longer than one second. Pressing HOLD key in Max/Min mode makes the meter stop updating the maximum or the minimum value. 1 push<1s Original state (Automatic/manual) 1 push>1s 1 push>1 sec 1 push>1 sec “MAX” active 1push<1s “MIN” active 1push<1s “Max” “MIN” blink min value current value max value Push HOLD 1push<1s Push HOLD Push HOLD “MAX”“MIN” “H” blink “MIN” “H” active “MAX” “H” active hold max value. 1push<1s hold min value. 1push<1s hold current value. 1push<1s 3.5 VAHz function When voltage or current measurement mode is selected, the VAHz funtion is available. Push VAHz key to select this frequency measurement mode. The frequency is measured by auto ranging. The maximum frequency range is 100kHz. The sensitivity of signal input is 10% full scale of voltage or current mode typically. Configuration FR1 FR2 FR3 Ver 2.9 Range 3.000KHz 30.00KHz 100.0KHz 15 10/06/25 ES51926 3000 Counts Smart DMM 3.6 Back light function When BKSEL is set to DGND or floating, push the BKLIT key to enable the back light output driving ON/OFF. If the auto back light configuration is active, the BKLIT becomes a control input for external light sensed circuit. Set to low for one second to active the back light output driving. Set to high then the driving output is inactive immediately. BKSEL DGND or floating V- 4. Configuration Normal back light function Auto back light function Miscellaneous The conditions, which the meter turns on the buzzer, include: (1) Changing measurement mode generates one beep. (2) Pressing any of the push functions generates one beep, if the function is valid. (3) Power on and re-power on generate one beep. (4) Input overflow in voltage and current mode generates one beep every 0.3 seconds (or 3.33 beeps per second.) (5) Continuity (diode) check generates a continuous 2KHz beep whenever the measurement is less then 30Ω(30mV) (6) Auto power off or power down by SEL key generates a 2KHz beeper that lasts for 1.5 seconds. The following figures show the output waveform from the BUZOUT pin. 0.5 mS (a) Continuous 2KHz beep 0.15 sec 0.3 sec (b) 3.33 beep/sec Ver 2.9 16 10/06/25 ES51926 3000 Counts Smart DMM 4.1 LCD configuration S1 BP1 S2 S3 S14 S12 S7 S8 S9 S10 S11 S15 S4 S5 S6 SCAN AUTO MANU HOLD S13 MAX MIN APO BP2 µ2 m2 V A AC n µ1 m1 F BP3 DC M K Ω Hz BP4 BATT SEG01 SEG02 SEG03 SEG04 SEG05 SEG06 SEG07 SEG08 SEG09 BP1 SCAN AUTO BP2 AC BP3 DC BP4 BATT DP3 A4 F4 E4 D4 MANU B4 G4 C4 A3 F3 E3 D3 HOLD B3 G3 C3 F2 E2 DP2 APO A2 G2 D2 B2 C2 DP1 SEG10 SEG11 SEG12 SEG13 SEG14 SEG15 BP1 A1 BP2 F1 BP3 BP4 Ver 2.9 µ2 M n MAX B1 m2 K µ1 MIN E1 G1 V Ω m1 D1 C1 A F 17 Hz 10/06/25 ES51926 3000 Counts Smart DMM LCD Backplane Waveform V- +3.2 VV- +3.2 VV- +3.2 VV- +3.2 VV- +3.2 V- 4.2 LCD display on condition LCD annunciates V A Ω F Hz DC AC SCAN AUTO MANU HOLD Max / Min m1 µ1 n m2 µ2 M K APO Ver 2.9 Condition In voltage measurement mode, and diode measurement mode. In current measurement mode. In resistance measurement mode, and continuity mode. In capacitance measurement mode. In continuity check mode. In diode mode. In VAHZ frequency mode. In DC voltage or DC current mode. In AC voltage or AC current mode. When auto scan mode is selected When automatic full scale range selection is enabled. In manual mode. When the reading is exceeding 30V in DCV or ACV, the DNAGER symbol will be displayed on When HOLD function is enabled. When delay-hold is selected, the HOLD symbol will be blinking for 6 seconds. When Max or Min function is enabled. In capacitor measurement mode and the full scale range is in the order of mF. In capacitor measurement mode and the full scale range is in the order of uF. In capacitor measurement mode and the full scale range is in the order of nF. In voltage or current measurement mode and the full scale range is in the order of 10-3. In current measurement mode and the full scale range id in the order of uA. In resistance measurement mode and the full scale range is in the order of MΩ In resistance measurement mode and the full scale range is in the order of KΩ When auto power off function is enabled. 18 10/06/25 ES51926 3000 Counts Smart DMM Test Circuit 1. Voltage test 4. Current test AGND OVSG 100 1K 10K 101K 1.111M D1 OR1 VR5 VR4 VR3 VR2 ADO D2 +1.0u ADI ACVL ACVH TEST5 15K 15K 10K +4.7u 10K 0.005 AGND SGND 30A 0.495 mA 4.5 A V R 100K uA uA mA uA V R 1 mA 50 100K 5. Diode test 10M AGND -400mV Z1 6V Z2 2. Resistance test 22n 220n OHMC3 470n PTC 1.5K 47n 100 Z1 6V Z2 100 1K 10K 101K 1.111M OVH 100 Voltage input OVX OHMC4 IVSH IVSL 450 PTC 1.5K VR1 10M 1.111M VR2 OHMC2 OVSG OHMC1 OVH OVSG 6. Low battery OR1 VR5 VR4 VR3 VR2 9V 680K BA SGND AGND LBAT9 TT 270K 0.1u AGND V- 0V 3. Current test for clampmeter 7. EF test EFin+ RL VR R 100K 100k 60M ADP SGND EFin- AGND SGND AGND VA+ 400mV Ver 2.9 ADP 19 VA- 10/06/25 ES51926 3000 Counts Smart DMM Application Circuit a.) AC average rectified circuit 1 2 3 4 6 5 V- C7 C8 0.495 R7 R8 IVSH R9 R10 IVSL 100K 60A SW6 1 J2 R6 R5 220pF 20K 1 SW7 J4 R17 SW SPST VR1_10M R / C / D / Cont. C6 VR1 0.005 Gnd 0.47uF 4MHz SEG10 SEG11 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 mA SW5 1.5K PTC ZR7 ZR8 1 C9 220nF LBAT 0.1uF 220nF 220K 75K 100K 100K R11 100 R12 R13 R14 R15 R18 100 1K 10K 101K 1.11M TEST5 ACVL ACVH ADI ADO J3 B C11 C13 22nF 220nF AGND DGND V+ V+ VVCC+ CESEL BKSEL OSC1 OSC2 SEG01 SEG02 SEG03 SEG04 SEG05 SEG06 SEG07 SEG08 SEG09 NC NC SEG10 SEG11 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 AGND LBAT CREF+ CREFCINT CAZ BUFF RAZ IVSH IVSL OVX OVH OVSG OR1 VR5 VR4 VR3 VR2 TEST5 ACVL ACVH ADI ADO OHMC4 OHMC3 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 SEG12 SEG13 SEG14 SEG15 CLAMP VON AON FA FUA FC3 FC2 FC1 HOLD SEL VAHz RANGE MAX/MIN BKLIT EFEN BP1 BP2 BP3 BP4 ANNUNC BKOUT ES51926 SEG12 SEG13 SEG14 SEG15 CLAMP VON AON FA FUA FC3 FC2 FC1 HOLD SEL VAHZ RANGE MZX/MIN BKLIT EFEN BP1 BP2 BP3 BP4 ANNUNC D J1 SEG01 SEG02 SEG03 SEG04 SEG05 SEG06 SEG07 SEG08 SEG09 SEG10 SEG11 SEG12 SEG13 SEG14 SEG15 BP1 BP2 BP3 BP4 U1 R4 60A 7.5V ZR6 4.5 C ZR4 C2 0.1uF mA SW4 R3 ZR5 0.1uF LCD Panel SEG01 SEG02 SEG03 SEG04 SEG05 SEG06 SEG07 SEG08 SEG09 45 C4 C1 10uF + R2 10uF + uA SW3 5.6V C3 C5 450 ZR3 Y1 ZR2 CESEL BKSEL R1 OHMC2 OHMC1 NC VRH VR SGND ADP VA+ VAVR1 NC CACA+ R9K R1K SLEEP BUZIN APOSEL BUZOUT ACEN NC NC NC NC NC ZR1 + SW2 SW1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 C CON19 Function Switch VBKLIT VCLAMP SW8 SW_non lock VON MZX/MIN SW9 SW_non lock RANGE AON SW10 SW_non lock VAHZ SW11 FA SW_non lock C10 ADI R21 15K R22 15K 47nF C12 R23 1uF 27K VR3 VR 10K 1uF + D1 1N4148 D2 ACVH IN4148 ADO 1 J5 ACVL A FC3 FC2 SLEEP FC1 R26 9K EFEN 220nF ZR9 R25 1K 4 SW_lock SW16 SW_lock SW17 B SW_lock SW18 SW_lock SW19 SW_lock SW20 SW_lock SW21 SW_lock SW22 SW_lock BZ1 Buzzer A ES51926 3000 Counts Smart DMM Number Revision Application Circuit ( Average ) 30-Aug-2007 D:\Protel file\ES51928 Serial.ddb 5 Sheet of Drawn By: 6 Notes: 1. The ESD protection circuits protect most of pins. However pins, V+, V-, AGND, DGND and VR1 are not protected enough because the parasitic effect must be decrease. Therefore enough external protection is needed for assembling, carrying and keeping. In addition, components connecting to these unprotected pins have to be soldered on board before the IC is soldered. 2. All the zener diodes above are used for IC protection. These protections are needed and these zener diodes must be soldered on PCB first before soldering ES51926 on. 3. The OVX pin resistance have to be kept below 120kΩ for the capacitance mode accuracy (3/30nF range). For higher voltage protection, additional configuration of PTC protection is necessary. 20 SW_lock SW15 5.6V B Ver 2.9 SW14 V- Date: File: 3 SW13 SW_non lock Size 2 HOLD FUA SW_non lock Title 1 SW12 BUZIN C18 ADP SEL APOSEL R24 C17 C15 TEST5 4.7uF C16 10K 100K R16 470nF VR1_10M R20 10K C14 + VR2 + Average Circuit 26 27 28 56K 29 30 31 32 VA+ 33 34 VA10M 35 36 470nF 37 38 39 40 41 42 43 44 45 46 47 48 49 50 SW SPDT R19 D 3V + BT1 uA 10/06/25 ES51926 3000 Counts Smart DMM b.) AC RMS circuit 4 SW4 mA 45 R3 R4 C8 0.495 60A SW10 MZX/MIN SW6 SW SPST VR1_10M SW_non lock SW7 SW_non lock ZR7 220K 75K 100K 100K 1.5K PTC R12 100 R13 R14 R15 R16 R17 100 1K 10K 101K 1.11M ACVL ACVH ZR8 ADO R / C / D / Cont. SW11 1 SW_non lock ACV / RMS J4 SW17 SW_lock SW_non lock C10 C12 22nF 220nF AGND DGND V+ V+ VVCC+ CESEL BKSEL OSC1 OSC2 SEG01 SEG02 SEG03 SEG04 SEG05 SEG06 SEG07 SEG08 SEG09 NC NC SEG10 SEG11 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 AGND LBAT CREF+ CREFCINT CAZ BUFF RAZ IVSH IVSL OVX OVH OVSG OR1 VR5 VR4 VR3 VR2 TEST5 ACVL ACVH ADI ADO OHMC4 OHMC3 TRMS Circuit SW_non lock -VS_ES7 B VR2 +VS_ES7 500K C13 470nF C14 47nF FUA FC3 A FC2 FC1 EFEN -VS_ES7 SW_lock SW18 SW_lock SW19 C17 + 10uF 10uF R19 R20 150 47K ACVH R21 ES7 C19 2.2uF 1uF 27K VR3 VR 10K + C20 2.2uF VR4 50K C18 1uF C15 C11 8 7 6 5 100K COM + VS Vout Cav U2 +VS_ES7 C16 RL Vin PwrDown - VS + 1 2 3 4 ES7_PWR + FA SW_lock SW15 SW_lock SW16 C B APOSEL BUZIN SLEEP R24 9K V- R25 AON 10K SW14 + VON SEG12 SEG13 SEG14 SEG15 CLAMP VON AON FA FUA FC3 FC2 FC1 HOLD SEL VAHZ RANGE MZX/MIN BKLIT EFEN BP1 BP2 BP3 BP4 ANNUNC ES7_PWR R18 VR1_10M R23 VCLAMP 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 SEG12 SEG13 SEG14 SEG15 CLAMP VON AON FA FUA FC3 FC2 FC1 HOLD SEL VAHz RANGE MAX/MIN BKLIT EFEN BP1 BP2 BP3 BP4 ANNUNC BKOUT ES51926 R22 SW13 R7 LBAT 0.1uF 220nF 220pF 20K 1 J3 C9 220nF C6 VR1 0.005 Gnd SW_non lock SW12 R6 R5 SW5 R8 R9 IVSH R10 R11 IVSL 100K 60A SW9 1 J2 HOLD 7.5V OHMC2 OHMC1 NC VRH VR SGND ADP VA+ VAVR1 NC CACA+ R9K R1K SLEEP BUZIN APOSEL BUZOUT ACEN NC NC NC NC NC C7 V- SEL D 26 27 28 56K 29 30 31 32 VA+ 33 VA34 10M 35 36 470nF 37 38 39 40 41 42 43 44 45 46 47 48 49 50 mA SW8 C VAHZ C2 0.1uF ZR6 4.5 CON19 RANGE 0.1uF ZR4 C1 10uF U1 ZR5 Function Switch BKLIT C4 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 R2 4MHz uA 10uF 0.47uF SW3 5.6V C3 C5 450 ZR3 Y1 ZR2 + 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 R1 V- + ZR1 SW SPDT + SEG01 SEG02 SEG03 SEG04 SEG05 SEG06 SEG07 SEG08 SEG09 SEG10 SEG11 SEG12 SEG13 SEG14 SEG15 BP1 BP2 BP3 BP4 D uA SW2 SW1 J1 3V + LCD Panel 6 5 BT1 SEG10 SEG11 3 SEG01 SEG02 SEG03 SEG04 SEG05 SEG06 SEG07 SEG08 SEG09 2 CESEL BKSEL 1 C21 ADP ADO 1 ZR9 220nF R26 1K BZ1 Buzzer J5 SW_lock SW20 5.6V SW_lock SW21 A SW_lock SW22 Title SW_lock SW23 Size B SW_lock Date: File: 1 2 3 4 ES51926 3000 Counts Smart DMM Number 5 21 Sheet of Drawn By: 6 Notes: 1. The ESD protection circuits protect most of pins. However pins, V+, V-, AGND, DGND and VR1 are not protected enough because the parasitic effect must be decrease. Therefore enough external protection is needed for assembling, carrying and keeping. In addition, components connecting to these unprotected pins have to be soldered on board before the IC is soldered. 2. All the zener diodes above are used for IC protection. These protections are needed and these zener diodes must be soldered on PCB first before soldering ES51926 on. 3. The OVX pin resistance have to be kept below 120kΩ for the capacitance mode accuracy (3/30nF range). For higher voltage protection, additional configuration of PTC protection is necessary. Ver 2.9 Revision Application Circuit ( TRMS ) 30-Aug-2007 D:\Protel file\ES51928 Serial.ddb 10/06/25 ES51926 3000 Counts Smart DMM Package Information 7.1 100 Pin LQFP Package 7.2 Dimension Parameters Ver 2.9 22 10/06/25