2 layers40.1 × 40.1 mm
Overview
The L7987 is a DC DC Converter made by STMicroelectronics in a HTSSOP-16-EP package with 17 pins. -40℃~+150℃@(TJ) 1 1mA 3A 4.5V~61V Adjustable Buck Buck Built-in No HTSSOP-16-EP DC-DC Converters ROHS.
PCBKit's library has its KiCad symbol (EasyEDA_Cloud:L7987LTR, from EasyEDA) and its footprint (EasyEDA_Cloud:HTSSOP-16_L5.0-W4.4-P0.65-LS6.4-BL-EP, from EasyEDA), ready for a KiCad board. 1,031 are in stock at JLCPCB (part C2832776). 2 open-source boards in 1 repository on GitHub use it.
Symbol
Footprint
From the datasheet
12- Supply, least
- 4.5 V · VIN, recommended operating min · p. 1
- Supply, most
- 61 V · VIN, recommended operating max · p. 1
- Supply, absolute maximum
- 61 V · VIN, absolute maximum · p. 7
- Junction, hottest
- 150 °C · junction operating temperature max · p. 7
- Takes working
- 2.5 mA · VIN and VCC quiescent typical, VBIAS = GND, LX floating, VFB = 1 V · p. 8
- Takes working
- 2.6 mA · sum of VIN/VCC and VBIAS quiescent typical, VBIAS = 3.3 V, LX floating, VFB = 1 V · p. 8
- Takes asleep
- 11 µA · VIN shutdown current typical, VEN = GND · p. 8
- Gives
- 3 A · continuous DC output current max · p. 1
- Current limit
- 4 A · peak current limit typical, ILIM floating, VFB = 0.6 V · p. 8
- Feedback reference
- 800 mV · feedback voltage typical · p. 9
- Switches at
- 250 kHz · switching frequency typical, FSW floating · p. 8
- Junction to air (HTSSOP16)
- 40 K/W · junction to ambient on demonstration board · p. 30
What it is and has
14- Output current
- 3 A DC · p. 1
- Input voltage
- 4.5 V to 61 V · p. 1
- Switching frequency
- Adjustable, 250 kHz - 1.5 MHz · p. 1
- Output voltage
- Adjustable from 0.8 V to VIN · p. 1
- Synchronization
- Supported · p. 1
- Soft-start
- Adjustable · p. 1
- Current limitation
- Adjustable · p. 1
- Auxiliary bias
- VBIAS improves efficiency at light load · p. 1
- Power good
- PGOOD open collector output · p. 1
- Output voltage sequencing
- Supported · p. 1
- Protection
- Digital frequency foldback in short-circuit · p. 1
- Protection
- Peak current foldback in short-circuit · p. 1
- Protection
- Auto-recovery thermal shutdown · p. 1
- Package
- HTSSOP16 · p. 1
Around it
4- cap 1 F
- between VBIAS and GND; Ceramic; required when VBIAS is supplied by the output voltage or an auxiliary rail. Connect VBIAS to signal GND if unused. · p. 6
- cap 1 F
- between VCC and GND; Ceramic; bypass to signal GND. · p. 6
- cap 100 nF
- between BOOT and LX; Typical bootstrap capacitor. · p. 6
- cap 1 F or higher
- between VIN and GND; Place as close as possible to the input voltage pin to filter high frequency noise. · p. 30
Specifications
71| Parameter | Conditions | As printed | Page |
|---|---|---|---|
| VIN VIN | min -0.3 · max 61 V | 7 | |
| VCC VCC | min -0.3 · max 61 V | 7 | |
| VBOOT - GND BOOT | min -0.3 · max 65 V | 7 | |
| VBOOT - VLX BOOT | min -0.3 · max 4 V | 7 | |
| VBIAS VBIAS | Maximum = VCC | min -0.3 V | 7 |
| EN EN | Maximum = VCC | min -0.3 V | 7 |
| PGOOD PGOOD | Maximum = VCC | min -0.3 V | 7 |
| LX LX | Maximum = VIN + 0.3 V | min -0.3 V | 7 |
| SYNCH SYNCH | min -0.3 · max 5.5 V | 7 | |
| SS SS | min -0.3 · max 3.6 V | 7 | |
| FSW FSW | min -0.3 · max 3.6 V | 7 | |
| COMP COMP | min -0.3 · max 3.6 V | 7 | |
| ILIM ILIM | min -0.3 · max 3.6 V | 7 | |
| FB FB | min -0.3 · max 3.6 V | 7 | |
| Operating temperature range TJ | Junction temperature | min -40 · max 150 °C | 7 |
| Storage temperature range TSTG | min -65 · max 150 °C | 7 | |
| Lead temperature (soldering 10 sec.) TLEAD | Soldering 10 sec. | max 260 °C | 7 |
| High-side RMS current IHS | max 3 A | 7 | |
| Thermal resistance junction-ambient (device soldered on the STMicroelectronics® demonstration board) RthJA | HTSSOP16; device soldered on the STMicroelectronics® demonstration board | typ 40 °C/W | 7 |
| HBM ESD | HBM | max 2 KV | 7 |
| CDM ESD | CDM | max 500 V | 7 |
| Operating input voltage range VIN | TJ = -40 to +125 °C; footnote 1 | min 4.5 · max 61 V | 8 |
| High side RDSON RDSON HS | ISW = 0.5 A; TJ = 25 °C | typ 0.2 · max 0.32 | 8 |
| High side RDSON RDSON HS | ISW = 0.5 A; TJ = -40 to +125 °C; footnote 1 | typ 0.2 · max 0.42 | 8 |
| Switching frequency fSW | FSW floating; TJ = 25 °C | min 233 · typ 250 · max 267 kHz | 8 |
| Switching frequency fSW | FSW floating; TJ = -40 to +125 °C; footnote 1 | min 225 · typ 250 · max 275 kHz | 8 |
| Selected switching frequency fSW | RSW = 10 k | min 1350 · typ 1500 · max 1650 kHz | 8 |
| Peak current limit IPK | ILIM floating; VFB = 0.6 V; footnote 2 | min 3.4 · typ 4 · max 4.6 A | 8 |
| Selected peak current limit IPK | RILIM = 100 k VFB = 0.6 V; footnote 2 | min 0.68 · typ 0.85 · max 1.01 A | 8 |
| Pulse skipping peak current ISKIP | Footnote 2 | typ 0.5 A | 8 |
| Feedback foldback level VFOLD | Not tested in production; footnote 3 | typ 400 mV | 8 |
| Maximum on time TONMAX | typ 12 us | 8 | |
| Minimum on time TONMIN | typ 120 · max 150 ns | 8 | |
| Minimum off time TOFFMIN | Not tested in production; footnote 3 | typ 360 ns | 8 |
| VCC UVLO rising threshold VCCH | TJ = -40 to +125 °C; footnote 1 | min 3.85 · typ 4.1 · max 4.3 V | 8 |
| VCC UVLO hysteresis VCCHYST | TJ = -40 to +125 °C; footnote 1 | min 160 · typ 250 · max 340 mV | 8 |
| VBIAS threshold SWO | Switch internal supply from VCC to VBIAS. VBIAS ramping up from 0 V. TJ = -40 to +125 °C; footnote 1 | min 2.84 · typ 2.9 · max 2.96 V | 8 |
| VBIAS threshold SWO | Hysteresis; not tested in production; footnote 3 | typ 80 mV | 8 |
| VCC - VBIAS threshold SWO | Switch internal supply from VCC to VBIAS. VIN = VCC = 24 V, VBIAS falling from 24 V to GND. TJ = -40 to +125 °C; footnote 1 | min 3.35 · typ 4.05 · max 4.9 V | 8 |
| VCC - VBIAS threshold SWO | Hysteresis; not tested in production; footnote 3 | typ 750 mV | 8 |
| Shutdown current from VIN ISHTDWN | VEN = GND | typ 11 · max 16 A | 8 |
| Quiescent current from VIN and VCC IQUIESC | LX floating, VFB = 1 V, VBIAS = GND, FSW floating | typ 2.5 · max 3.4 mA | 8 |
| Quiescent current from VIN and VCC IQOPVIN | LX floating, VFB = 1 V, VBIAS = 3.3 V, FSW floating | typ 1 · max 1.4 mA | 8 |
| Quiescent current from VBIAS IQOPVBIAS | LX floating, VFB = 1 V, VBIAS = 3.3 V, FSW floating | typ 1.6 · max 2.4 mA | 8 |
| Device OFF level VEN | min 0.06 · max 0.3 V | 9 | |
| Device ON level VEN | min 0.35 · max 0.9 V | 9 | |
| Soft start setup time TSSSETUP | Delay from UVLO rising to switching activity; not tested in production; footnote 3 | typ 640 s | 9 |
| CSS charging current ISS CH | VSS = GND | min 4.3 · typ 5 · max 5.7 A | 9 |
| Voltage feedback VFB | TJ = 25 °C | min 0.792 · typ 0.8 · max 0.808 V | 9 |
| Voltage feedback VFB | TJ = -40 to +125 °C; footnote 1 | min 0.788 · typ 0.8 · max 0.812 V | 9 |
| VCOMPH VCOMPH | VFB = GND; VSS = 3.2 V | min 3.2 · typ 3.35 · max 3.5 V | 9 |
| VCOMPL VCOMPL | VFB =1 V; VSS = 3.2 V | max 0.1 V | 9 |
| FB biasing current IFB | VFB =3.6 V | typ 5 · max 50 nA | 9 |
| IOSOURCE IOSOURCE | VFB =GND; SS pin floating; VCOMP =2 V; not tested in production; footnote 3 | typ 3.1 mA | 9 |
| Output stage sinking capability IOSINK | Unity gain buffer configuration (FB connected to COMP). COMP voltage variation due to IOSINK injection lower than ± 0.1 · VFB; not tested in production; footnote 3 | typ 5 mA | 9 |
| Error amplifier gain AV0 | Not tested in production; footnote 3 | typ 100 dB | 9 |
| GBWP GBWP | Unity gain buffer configuration (FB connected to COMP). No load on COMP pin. Not tested in production; footnote 3 | typ 23 MHz | 9 |
| Synchronization frequency fSYN MIN | FSW floating | min 280 kHz | 9 |
| Master output amplitude VSYNOUT | ILOAD = 4 mA | min 2.45 V | 9 |
| Master output amplitude VSYNOUT | ILOAD = 0 A; pin SYNCH floating | max 3.8 V | 9 |
| Output pulse width VSYNOW | ILOAD = 0 A; pin SYNCH floating | min 155 · typ 225 · max 275 ns | 9 |
| SYNCH slave high level input threshold VSYNIH | min 2 V | 9 | |
| SYNCH slave low level input threshold VSYNIL | max 1 V | 9 | |
| Slave SYNCH pull-down current ISYN | VSYNCH = 5 V | min 550 · typ 750 · max 950 A | 9 |
| Input pulse width VSYNIW | min 200 ns | 9 | |
| PGOOD rising threshold VPGDTH | VFB rising | min 0.67 · typ 0.7 · max 0.73 V | 9 |
| PGOOD hysteresis VPGDHYST | VFB falling; not tested in production; footnote 3 | typ 30 mV | 9 |
| PGOOD low level VPGDLOW | IPGD = 1 mA, VFB = GND | typ 30 mV | 10 |
| PGOOD leakage current IPGDLKG | VPGOOD = 61 V;VFB = 0.8 V | max 0.1 A | 10 |
| Thermal shutdown temperature TSHDWN | Not tested in production; footnote 3 | typ 170 °C | 10 |
| Thermal shutdown hysteresis THYS | Not tested in production; footnote 3 | typ 15 °C | 10 |
Pins, by the datasheet
17- 1 VBIAS
- Auxiliary analog supply, typically connected to the regulated output or an external rail higher than 3 V; connect to signal GND if unused, otherwise bypass with a 1 uF ceramic capacitor. · p. 6
- 2 VIN
- DC input voltage. · p. 6
- 3 VIN
- DC input voltage. · p. 6
- 4 VCC
- Filtered DC input voltage to internal circuitry; bypass to signal GND with a 1 uF ceramic capacitor. · p. 6
- 5 EN
- Active high enable; connect to VCC if unused. · p. 6
- 6 SS
- An internal current generator charges the external soft-start capacitor. · p. 6
- 7 SYNCH
- Master / slave synchronization. · p. 6
- 8 COMP
- Error amplifier output; connect the compensation network here. · p. 6
- 9 FB
- Inverting input of the error amplifier. · p. 6
- 10 FSW
- A pull-down resistor to GND selects the switching frequency. · p. 6
- 11 ILIM
- A pull-down resistor to GND selects the peak current limitation. · p. 6
- 12 PGOOD
- Open collector output driven low when the output voltage sensed on FB is out of regulation. · p. 6
- 13 LX
- Switching node. · p. 6
- 14 LX
- Switching node. · p. 6
- 15 BOOT
- Connect an external capacitor, typically 100 nF, between BOOT and LX to supply the internal n-DMOS gate charge. · p. 6
- 16 GND
- Signal GND. · p. 6
- - E.P.
- Exposed pad must be connected to signal GND. · p. 6
Ordering codes, by the datasheet
2- L7987
- HTSSOP16 · Tube packaging · p. 36
- L7987TR
- HTSSOP16 · Tape and reel packaging · p. 36
Parameters
19- Current Limit
- 4A
- Features
- Operating status indication
- Frequency - Switching
- 250kHz
- Function
- Step-down type
- Junction Temperature(Max)
- 150℃
- Number of Outputs
- 1
- Operating Temperature
- -40℃~+150℃@(TJ)
- Output Current
- 3A
- Output Type
- Adjustable
- Output Voltage
- 800mV~61V
- Quiescent Current
- 1mA
- Reference Voltage
- 800mV
- Standby Current
- 11uA
- Switch tube (built-in/external)
- Built-in
- Synchronous Rectifier
- No
- Thermal Resistance(Junction to Ambient)
- 40℃/W
- Topology
- Buck
- Voltage - Supply
- 4.5V~61V
- Voltage - Supply(Absolute Max)
- 61V
Order codes
2- L7987LCSC C1355783
- L7987TRLCSC C2832776
Pinout
17| Pin | Name | Type |
|---|---|---|
| 1 | VBIAS | Unspecified |
| 2 | VIN | Unspecified |
| 3 | VIN | Unspecified |
| 4 | VCC | Unspecified |
| 5 | EN | Unspecified |
| 6 | SS | Unspecified |
| 7 | SYNCH | Unspecified |
| 8 | COMP | Unspecified |
| 9 | FB | Unspecified |
| 10 | FSW | Unspecified |
| 11 | ILIM | Unspecified |
| 12 | PGOOD | Unspecified |
| 13 | LX | Unspecified |
| 14 | LX | Unspecified |
| 15 | BOOT | Unspecified |
| 16 | GND | Unspecified |
| 17 | EP | Unspecified |
Open-source boards using it
All 2- 2 layers40.1 × 40.1 mm
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Is there a KiCad symbol and footprint for the L7987?
Yes. The symbol is EasyEDA_Cloud:L7987LTR and the footprint EasyEDA_Cloud:HTSSOP-16_L5.0-W4.4-P0.65-LS6.4-BL-EP, both drawn on this page. PCBKit places them on a board for you when you design with it.
What package is the L7987?
HTSSOP-16-EP, with 17 pins. Its footprint is drawn on this page.
Where is the L7987 datasheet?
STMicroelectronics publishes it: the Datasheet link on this page opens it.
Where can I order the L7987?
JLCPCB lists it as part C2832776, with 1,031 in stock; the sellers' links on this page open their listings.
What can replace the L7987?
Parts like it in the library: the TPS54395PWP by Texas Instruments, the LT1765EFE-5#PBF by Analog Devices, the LT3430EFE#TRPBF by Analog Devices and the LT1374CFE#TRPBF by Analog Devices. Check their datasheets: a part that fits the footprint may still differ in its ratings.
Which open-source boards use the L7987?
2 boards in 1 repository on GitHub; the most starred are listed on this page, with their KiCad files.
Parts like it
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