LM134Z - 3-Terminal Adjustable Current Source, 10mA, 40V | STMicroelectronics
Référence : LM134Z ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $3.92 | $3,92 |
| 10 | $3.45 | $34,50 |
| 100 | $2.88 | $288,00 |
| 500 | $2.41 | $1 205,00 |
| 1 000 | $1.97 | $1 970,00 |
LM134Z Présentation
An adjustable current source is a fundamental analog building block that delivers a precise, supply-independent current into a load, regardless of the voltage developed across it. Within the broader component taxonomy, the LM134Z sits at the level of: current source / current regulator -> analog functional IC -> integrated circuit -> semiconductor. LM134-class devices are used as constant-current biasing elements, low-temperature-co references, and as temperature sensors because the programming current is proportional to absolute temperature (PTAT) by approximately 0.96 %/°C after correction.
Key features include a wide dynamic voltage compliance of 1 V to 40 V (per TI's equivalent datasheet for the same LM134 family), an initial current accuracy of ±3 %, and true floating two-terminal operation that allows the device to be stacked in series with any load. The 10,000:1 programmable range makes it suitable for both micropower biasing (µA range) and modest supply-level driving (mA range). Available in a TO-92-3 through-hole package, the LM134Z is widely used on breadboards, in linear regulators, and in test instrumentation.
The LM134 family is implemented with a bipolar transistor architecture using a bandgap-style reference and an internal current mirror; this architecture is the reason the device is inherently PTAT and can be used as a temperature sensor by reading the programming resistor voltage. The military temperature grade (-55 °C to +125 °C) and 400 mW power dissipation rating support harsh-environment designs. Quiescent current is established solely by the programming resistor, so no separate supply current exists beyond the programmed load current.
Typical applications include low-temperature-co zener biasing, battery charging at constant current, ramp generators, and precision temperature sensing when paired with an op-amp readout. In bias networks for transistors and op-amps, the LM134Z provides a stable reference current that does not drift with supply voltage variations. Industrial process control loops and instrumentation also benefit from the LM134Z's predictable PTAT behavior.
When designing with the LM134Z, calculate the programming resistor as R_set = (67.7 mV / I_set) at 25 °C; this sets the nominal current. Add a series resistor of approximately 10× R_set in parallel with R_set to flatten the temperature coefficient if a low-TC bias is desired. Always ensure the load voltage plus the 0.8 V minimum compliance remains within the 40 V absolute maximum rating.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, including verified cross-brand pin-compatible equivalents and parametric proximity scoring.
Alternatives de remplacement direct pour LM134Z — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
LM234Z
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LM134H
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LM334Z
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LM334Z/NOPB
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LM334M
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
LM234Z
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LM134Z Valeurs maximales et caractéristiques électriques
| Part Number | LM134Z |
| Manufacturer | STMicroelectronics |
| Fonction | 3-terminal adjustable current source |
| Operating Current Range | 1 µA to 10 mA (10,000:1) |
| Terminal-to-Terminal Voltage Range | 0.8 V to 40 V |
| Initial Current Accuracy | ±3 % |
| Current Regulation | 0.02 %/V (typical) |
| Plage de température de fonctionnement | -55 °C to +125 °C (military grade) |
| Power Dissipation | 400 mW |
| Temperature Coefficient (untrimmed) | ~0.96 %/°C PTAT |
| Boîtier | TO-92-3 (through-hole) |
| Terminal Pitch | 1.27 mm |
| Type de montage | Through-Hole |
| Topologie | True floating 2-terminal current source |
| Programming Method | Single external resistor |
| Statut RoHS | unknown (TO-92 lead-bearing variant, depends on date code) |
| Lead-Free | unknown |
Configuration des broches de LM134Z
| Broche 1 | R — Programming resistor to ground; sets I_set = 67.7 mV / R_set |
| Broche 2 | Anode (+) — Positive terminal of the floating current source |
| Broche 3 | Cathode (-) — Negative terminal of the floating current source |
Applications typiques
LM134Z convient pour 7 applications: Low-Temperature-Coefficient Zener Biasing, Constant-Current Battery Charger, Precision Temperature Sensor (PTAT), Transistor and Op-Amp Bias Networks, Ramp and Sawtooth Waveform Generator, Industrial Process Control Loop Bias, LED Constant-Current Driver.
Low-Temperature-Coefficient Zener Biasing
The LM134Z's 0.02 %/V regulation and PTAT temperature coefficient make it ideal as a bias source for zener references, where the supply voltage varies but a stable bias current is required. Connected with R_set chosen to deliver 5 mA through a 6.2 V zener, the LM134Z holds zener current constant across supply variations from 8 V to 40 V. Adding a 10× R_set series resistor in parallel flattens the temperature coefficient to ~0.01 %/°C, which is critical for precision 5 V and 10 V voltage references used in digital multimeters and calibration equipment where the LM134Z's 1 µA to 10 mA range matches typical zener bias requirements exactly.
Recommandé
Constant-Current Battery Charger
The LM134Z functions as a constant-current battery charger for single-cell NiCd, NiMH, and small Li-ion packs by programming I_set via R_set to the desired charge rate (e.g., C/10). With 0.8 V to 40 V compliance, the LM134Z drives battery stacks from one cell up to ten cells in series; the device's true floating topology means it can be placed in series with the load without ground-reference issues. The 1 µA to 10 mA range covers both trickle-charge (µA) and fast-charge (mA) regimes. The ±3 % initial accuracy is acceptable for charger applications, and the TO-92-3 through-hole package simplifies hand-soldered prototyping of charger modules for portable medical or industrial sensor nodes.
Recommandé
Precision Temperature Sensor (PTAT)
Because the LM134Z's programming current is proportional to absolute temperature (PTAT) at approximately 0.96 %/°C untrimmed, the device paired with an op-amp readout forms a low-cost linear temperature sensor. The voltage across R_set rises ~2.04 mV/°C (a 10× scaled PTAT coefficient), which a simple op-amp buffer can digitize with an ADC. The military -55 °C to +125 °C operating range matches industrial and aerospace temperature-sensing requirements. The 0.02 %/V regulation ensures temperature readings are insensitive to supply variation, and the TO-92-3 package's small thermal mass gives fast time response (~1 s in still air), suitable for probe-style temperature measurements in process control and HVAC systems.
Recommandé
Transistor and Op-Amp Bias Networks
The LM134Z provides stable bias currents for transistor and op-amp stages in precision analog circuits, where supply-independent biasing is essential to maintain gain and offset over voltage variations. With 1 µA to 10 mA range and 0.02 %/V regulation, the LM134Z outperforms simple resistor biasing in current-mirror references, differential pair tail currents, and AGC stages. Replacing an emitter resistor with an LM134Z tail current source in a differential amplifier improves common-mode rejection ratio (CMRR) by eliminating supply-modulated tail current variation. The TO-92-3 package fits easily into discrete analog designs and instrumentation front-ends.
Recommandé
Ramp and Sawtooth Waveform Generator
The LM134Z combined with a capacitor and a periodic reset transistor forms a linear ramp generator with excellent linearity, because the constant charging current from the LM134Z (set by R_set) produces a linear voltage ramp across the capacitor. The 0.02 %/V regulation eliminates supply-dependent ramp slope errors, and the 1 µA to 10 mA range covers both slow timing ramps (µA) and fast sweep ramps (mA) for time-base and A/D converter test circuits. The TO-92-3 package makes this an inexpensive function generator building block for educational lab equipment, function generator modules, and analog timing circuits.
Recommandé
Industrial Process Control Loop Bias
The LM134Z's military temperature grade (-55 °C to +125 °C), 0.8 V to 40 V compliance, and high regulation (0.02 %/V) make it well suited for industrial 4-20 mA current loop and process-control instrumentation where reliable biasing across wide temperature and voltage ranges is mandatory. The LM134Z can be used as the loop excitation source for 4-20 mA transmitters, or as a stable reference for analog signal-conditioning front-ends. Its true floating topology allows it to be inserted anywhere in the signal chain without ground-reference issues, and the TO-92-3 through-hole package is well-suited to ruggedized industrial PCBs that prefer through-hole components for reliability.
Recommandé
LED Constant-Current Driver
The LM134Z drives LEDs and laser diode indicator loads at a precise, supply-independent current, eliminating the brightness variations that plague simple resistor biasing. Programming I_set to the LED's nominal drive current (e.g., 20 mA for standard indicator LEDs, though the LM134Z tops out at 10 mA so it suits lower-current LEDs and indicator lamps) via R_set produces a constant LED brightness across supply variations of 1 V to 40 V. The TO-92-3 package fits compact indicator and panel-illumination designs where board space is at a premium. For high-brightness LEDs above 10 mA, a current-mirror booster transistor can be added without affecting the LM134Z's stable bias reference.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour LM134Z — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | LM234Z | LM134H | LM334Z | LM334Z/NOPB | LM234Z (TI) |
|---|---|---|---|---|---|---|
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | TO-92-3 | TO-92-3 (same) | TO-92-3 (same) | TO-92-3 (same) | TO-92-3 (same) | TO-92-3 (same) |
| Operating Current Range | 1 µA to 10 mA | 1 µA to 10 mA | 1 µA to 10 mA | 1 µA to 10 mA | 1 µA to 10 mA | 1 µA to 10 mA |
| Terminal Voltage Range | 0.8 V to 40 V | 0.8 V to 40 V | 0.8 V to 40 V | 0.8 V to 40 V | 0.8 V to 40 V | 0.8 V to 40 V |
| Temperature Grade | -55 °C to +125 °C (military) | -25 °C to +100 °C (industrial) | -55 °C to +125 °C (military) | 0 °C to +70 °C (commercial) | 0 °C to +70 °C (commercial) | -25 °C to +100 °C (industrial) |
| Initial Accuracy | ±3 % | ±3 % | ±3 % | ±3 % | ±3 % | ±3 % |
| Current Regulation | 0.02 %/V | 0.02 %/V | 0.02 %/V | 0.02 %/V | 0.02 %/V | 0.02 %/V |
| Power Dissipation | 400 mW | 400 mW | 400 mW | 400 mW | 400 mW | 400 mW |
| Lead-Free / RoHS | unknown (TO-92 lead-bearing) | unknown | unknown | Contains Lead | Lead-Free / RoHS | unknown |
Principaux différenciateurs
- True floating two-terminal current source topology (vs LM317 (three-terminal adjustable regulator))
- Wide 10,000:1 programmable current range (vs LM334 (same die, lower temperature grade))
- PTAT temperature coefficient enables dual-use as temperature sensor (vs Discrete current mirror (BJT + resistor))
Notes de conception
The most common LM134Z design mistake is forgetting that the device is a true floating two-terminal current source, not a three-terminal device with separate supply. Current flows between pins 2 and 3; pin 1 (R) only sets the programming current via R_set to ground. Designers accustomed to three-terminal regulators often mis-wire the device. Always connect R_set between pin 1 and the same ground as the load return, and ensure the load voltage plus 0.8 V minimum compliance does not exceed 40 V absolute maximum. Reverse polarity on pins 2/3 will not damage the part but disables current flow.
The LM134Z's PTAT temperature coefficient (about 0.96 %/°C untrimmed) means that without compensation, the output current drifts significantly with temperature. To flatten the coefficient, add a series resistor between pin 1 (R) and ground that is approximately 10× the value of R_set. Per the LM134 family datasheet, this technique reduces the temperature coefficient to within ±0.01 %/°C over the -55 °C to +125 °C military grade range. Without this compensation, the LM134Z drifts ~1 %/°C, which is unacceptable for precision bias but acceptable for general-purpose bias or for temperature-sensing applications where PTAT drift is the desired signal.
For TO-92-3 through-hole PCB layout, place R_set as close as possible to pin 1 of the LM134Z to minimize parasitic resistance and noise pickup. Keep high-current traces away from the R pin; even small leakage currents (nA) at high-impedance R_set values (e.g., 67.7 kΩ for 1 µA) can shift the programmed current noticeably. Use a ground plane on the bottom layer to provide a clean reference for the programming resistor. For temperature-sensing circuits, mount the LM134Z thermally isolated from other heat sources (use thermal relief on the TO-92 leads during soldering) to ensure accurate temperature readings.
Maximum power dissipation for the LM134Z is 400 mW in free air at 25 °C, derated linearly above this temperature. Power dissipation is calculated as P_D = (V_compliance - V_load) × I_set + V_compliance × I_set (the device drops approximately 0.8 V to 1.5 V internally). At maximum I_set = 10 mA and 40 V compliance into a short circuit, P_D approaches 400 mW - the absolute maximum. Estimated: at I_set = 5 mA and 15 V supply into a 1 kΩ load, V_load = 5 V and P_D ≈ 0.4 W, requiring attention to ambient temperature. For continuous operation above 300 mW dissipation, mount the TO-92 vertically or add a small clip-on heatsink.
Informations de conformité
TO-92 lead-bearing package; RoHS/lead-free status depends on date code and is not explicitly documented in the verified web data. The TI LM334Z/NOPB is the explicitly lead-free variant per the TI datasheet, and is the recommended substitute where RoHS compliance is required.
